Resistance change type memories, such as an MRAM (Magnetoresistive RAM), an ReRAM (Resistive RAM), and a PCRAM (Phase change RAM), attract attention as a next-generation semiconductor memory. In the resistance change type memories, an increase in storage density and reduction of power consumption can be achieved by miniaturization of a memory element.
However, miniaturization of the memory element involves the difficulty of forming a stable contact between the memory element and an interconnect or a contact plug, and a process margin decreases.